Blocking mechanism for an overhead crane trackway

ABSTRACT

A device for blocking the movement of a movable crane on an overhead trackway when it comes to the end of the trackway includes a mechanism mounted at the end of the trackway and supporting a buffer arm having a buffer end portion thereon which is alignable with the trackway over which a crane is movable in order to block the movement of the crane toward the end of the trackway. The arrangement includes a motor drive for pivoting the buffer arm about an axis which is substantially parallel to the longitudinal axis of the trackway for the purpose of shifting the buffer arm from a position at which it blocks the moving crane to one at which it is removed from a blocking position to permit traveling movement of the crane from one trackway to another trackway which is aligned therewith. The adjacent trackway is adapted to have a similar buffer construction with a pivot lever element which is exposed when the two trackways are aligned in a position such that actuation of one buffer arm to move it out of a blocking position will be effective to move the other buffer arm of the adjacent trackway out of a blocking position.

[ Oct. 10, 1972 [54] BLOCKING MECHANISM FOR AN OVERHEAD CRANE TRACKWAYPrimary Examiner-Arthur L. La Point Assistant Examiner-Robert Saifer[72] Inventors: Fred Wiggershaus, Silschede; Klaus Donner, Hohenlimburg,both of and Germany 57 ABSTRACT [73] Asslgnee' gzTz Duisburg A devicefor blocking the movement of a movable crane on an overhead trackwaywhen it comes to the Filed! April 1970 end of the trackway includes amechanism mounted at the end of the trackway and supporting a buffer arm[2]] Appl' 30318 having a buffer end portion thereon which is alignablewith the trackway over which a crane is movable in Foreign ApplicationPriority Dam order to block the movement of the crane toward the end ofthe trackway. The arrangement includes a July 1969 Germany 19 36 3854motor drive for pivoting the buffer arm about an axis .104 250 which isSubstantially Parallel to the lhhghhdihal axis {7/00 of the trackway forthe purpose of shifting the buffer [58] Fie'ld 249 250 252 253 arm froma position at which it blocks the moving 6 1 1. 246/393 crane to one atwhich it is removed from a blocking position to permit travelingmovement of the crane from one trackway to another trackway which is[56] Rgferences Cited aligned therewith. The adjacent trackway isadapted UNITED STATES PATENTS to have a similar bulfer construction witha pivot lever element which is exposed when the two trackways are f gpbaligned in a position such that actuation of one buffer 20l7392 10/1935f I "5 arm to move it out of a blocking position will be effeca e tiveto move the other buffer arm of the adjacent FOREIGN PATENTS ORAPPLICATIONS trackway out of a blockmg I 821,368 11/1951 Germany..104/250 1 Claim, 2 Drawing Figures I l T .I 141 h 1' ZSYIIIIIIII;

PATENTEDum 10 I972 3.696, 755

Fig.1

73 I g ull lnven tors F250 W/GGERSHA U5 K LA [/5 DOA/MFR TI'OAWEYSBLOCKING MECHANISM FOR AN OVERHEAD CRANE TRACKWAY SUMMARY OF THEINVENTION This invention relates in general to the construction ofoverhead crane devices, and in particular, to a new and useful blockingdevice which includes a pivotal arm member carrying a buffer and whichis adapted to be located at an end position on a trackway and which ismovable between a position in which it blocks the movement of a craneoff the end of the trackway to one which permits the movement of thecrane for example, on to another trackway which is aligned with thefirst.

The present invention is particularly applicable to a deviceforcontrolling the movement of a crane along a crane trackway in order toprevent the crane. from dropping off the end. Such a blocking device isapplicable to all lifting devices such as trolleys, hoists, stackingcranes, etc., which travel on tracks which are moved transverselythemselves. The known blocking devices for preventing the movement offthe end of the trackway when it is not aligned with another trackwayincludes a pivoting arm device in which the arm is pivotable about anaxis disposed perpendicular to the crane track. The arm blocks the cranetrack in the lowered condition and it frees it in its raised condition.Raising of the pivot arms is accomplished by a linkage which is actuatedwhen two adjacent trackways are locked together. After unlocking thetrackways, the pivoting arms are supposed to drop due to their ownweight or due to a spring force. The pivoting devices do not functionperfectly when the friction in the bearings of the transmission linkagebecomes too great, or when the blocking device or parts thereof are bentdue to an overstressing. Preferably the blocking devices are equippedwith buffers to absorb the impact shocks. However, the buffers must notproject into the path of travel by the movable crane or trolley.Therefore, the blocking device protrudes far beyond the buffer andstresses it and the bearing of the blocking device through a lever armwhich further increases the stress. Weak forces only can be transmittedby the known blocking devices and for this reason they are suited forlight crane trackways only.

In accordance with the invention, a pivotable blocking device for heavyduty crane tracks or trackways is provided which is capable of operationwithout impairment and which is not subject to extraordinary bearingfriction or friction which is produced by deformed components. Theconstruction includes a buffer arm which is pivotable about an axiswhich is substantially parallel to the trackway axis and which is movedby a motor which is connected thereto such as by a driving sprocket andshaft connection. The motor is arranged to rotate in two directions ofrotation and thus can pivot the buffer both into a free position andinto a blocked position. The buffer element is attached to the pivotingarm which is mounted in a pivot housing attached to the crane trackway.The bearing points for the pivot housing may be spaced relatively farapart and the pivot arms are only so long that they can be swung withthe buffer out of the range of the suspended crane or the trolley.Because of this compact design no great forces will affect the bearingpoints when the crane impacts on the buffer.

According to another feature of the invention, the pivoting arm isconnected to the motor by a power transmission which may be, forexample, a drive shaft having a sprocket wheel and a chain engaging withthe wheel and a wheel of the motor. The drive may also be similar powertransmission such as gears or belts or the like. With the drive shaftdescribed, however, the motor may be located outside of the range of thecrane trackway so that it will not be block the movement of the crane.

Preferably, the buffer is carried on a rod member which is biased byspring means arranged in a cylinder housing and which provide adampening action. The construction permits attenuation of the impactshocks and also reduces noise due to the appropriate material selectionfor the damping buffer.

In accordance with a further feature of the invention the pivot armincludes a pivot plate which is disposed to actuate a similar pivotplate'of a buffering device of similar nature contained on the trackwaywhich may be aligned with the first trackway. The pivot plate of thefirst trackway is disposed horizontal to the shaft direction of thepivoting arm but is staggered in respect to height as to the adjacentpivot plate of the buffer mechanism of the next adjacent trackway. Thepivotal motion of the first buffer arm is transmitted to the secondbuffer arm when the two trackways are aligned. The horizontal staggeringof the two pivot plates permits the movement of the trackways beyond thealignment position.

Accordingly, it is an object of the invention to provide an improvedbuffering mechanism for an overhead trackway for cranes, trolleys andthe like, which includes a buffer arm member carried on the trackwayadjacent an end thereof and which is shiftable about an axissubstantially parallel to the trackway axis for the purpose ofpositioning the arm in a blocking position or in a free position inrespect to the associated trackway.

A further object of the invention is to provide a device for preventingthe movement of a traveling crane or trolley off the end of the trackwayor trackways which may be shifted transversely and, for example, alignedwith another trackway and which includes a pivotal arm member carrying abuffer on a first trackway which may be shifted between a blockingposition aligned with the trackway or a position offset from thetrackway and which includes lever means for actuating the adjacentbuffer mechanism to do the same thing.

A further object of the invention is to provide a buffering mechanismfor a trackway over which a crane or trolley is movable and which issimple in design, rugged in construction, and economical to manufacture.

The various features of novelty which characterize the invention arepointed out with particularity in the claims annexed to and forming apart of this specification. For a better understanding of the invention,its

trated and described a preferred embodiment of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS In the drawings:

FIG. 1 is a partial side elevational view partly broken away showing twotransversely aligned trackways over which a crane is movable and whichincludes a buffer mechanism constructed in accordance with theinvention; and

FIG. 2 is a section taken on the line 2-2 of FIG. 1.

GENERAL DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to thedrawings in particular, theinvention embodied therein is employed inassociation with a suspension or overhead crane system generallydesignated 50 which includes one or more trackways l, and 1 movable inrespective transverse areas and capable of being aligned so that theaxis of the trackways defined thereby may be aligned for movement of acrane or trolley 52 from one trackway onto the other. In the aligned'orflush position of the two trackways l and 1' they are prevented by meansof a holding device generally designated 13 from shifting laterally withrespect to each other.

In accordance with the invention, the trackways 1 and 1' each have abuffering mechanism or device generally designated 54 and 54,respectively, Each buffering mechanism 54 and 54 includes a resilientbuffer member which is carried on the end of a rod member 56 and whichis biased by springs 9 in a direction to project outwardly in theassociated trackway toward the interior of the trackway and in theactive position provides a buffer or stop for preventing o furthermovement of theassociated traveling crane or trolley 52. The springs 9provide for the attenuation of the shock upon impact of the crane 52against the buffer 10.

The cylinder 8 is attached to a pivoting arm 7 which is pivotallymounted in a pivot housing 6 for pivotal movement about an axis 11 whichis substantially parallel to the axis of the trackway. The housing 6 isfastened to the end of the associated trackway l or 1' at a location inwhich the buffer 10 will be spaced inwardly fromthe adjacent endthereof.

In accordance with a feature of the invention a motor 2 is mounted in anon-blocking position over the trackway 1 and it is equipped with asprocket wheel on chain 3 which is engaged'with a sprocket wheel 4 of adrive shaft 5. The drive shaft 5 is connected through a universal joint58 to a pivot member 60 for the arm 6. Rotation of the motor 2 in aselected direction will pivot the arm 6 between a blocking positionshown in solid lines to a dotted line position shown in FIG. 2 at whichit is located to free the movement of the crane 52 and will be free ofany blocking action in respect to the crane moving along the trackway.

In accordance with a further feature of the invention a pivot plate 12is attached to the member 11 and it rotates therewith during themovement of the arm 7. The plate 12 on the buffering mechanism 54 isoffset vertically from the corresponding plate 12 of the bufferingmechanism 54' so that it will not interfere with the transverse movementof one track I in respect to the other track 1'. However, when thetracks are aligned, rotatable movement of the plate 12 on the bufferingmechanism 54 will cause a corresponding rotatable movement of the plate12 on the buffering mechanism 54'.

What IS claimed is:

l. A blocking device for use with .a transversely movable trackway overwhich a train or trolley is moved, comprising a buffer arm member, meansmounting said buffer arm member adjacent the end of the trackway forpivotal movement between a blocking position blocking the end of thetrackway and a free.

position freeing the end of the trackway, and motor means connected tosaid buffer arm member for shifting said buffer arm member between saidblocking position and said free position, a first trackway carrying saidbuffer arm member, a second trackway carrying a second buffer arm membersimilar to said first member, said first buffer arm member and saidsecond buffer arm member having actuating plates thereon which arerotatable therewith and which project outwardly from the end of theassociated trackway, said first buffer arm member actuating plate beingrotatable with said arm and engageable with the actuating plate of saidsecond buffer arm member to rotate it, said plates being offsetvertically in order to permit transverse movement of said trackwaysrelative to each other.

* III

1. A blocking device for use with a transversely movable trackway overwhich a train or trolley is moved, comprising a buffer arm member, meansmounting said buffer arm member adjacent the end of the trackway forpivotal movement between a blocking position blocking the end of thetrackway and a free position freeing the end of the trackway, and motormeans connected to said buffer arm member for shifting said buffer armmember between said blocking position and said free position, a firsttrackway carrying said buffer arm member, a second trackway carrying asecond buffer arm member similar to said first member, said first bufferarm member and said second buffer arm member having actuating platesthereon which are rotatable therewith and which project outwardly fromthe end of the associated trackway, said first buffer arm memberactuating plate being rotatable with said arm and engageable with theactuating plate of said second buffer arm member to rotate it, saidplates being offset vertically in order to permit transverse movement ofsaid trackways relative to each other.